Effects Of The Activated Zn²⁺ Ions On The Expression Of The Matrix Metalloproteinase In Corneal Tissue After Alkali Burn

Purposes To investigate the main role of different matrix metalloproteinases in corneal melting pathological mechanism and to investigate inhibition of the production of matrix metalloproteinases by the intervention of the activated Zn2+ion in alkali-burned cornea.Methods Experimental animal model of alkali-burned cornea was established. Research applied gelatin enzyme spectrum, Western Blot technique and immunohistochemistry technique to observe the expression of matrix metalloproteinase-1,2and9in3days,1week and1month after alkali-burn-induced corneal melting. The0.1mmol/L and1mmol/L Zn2+ions solution were applied after alkali burn of corneal tissue. The expression of metalloproteinase-1,2and9were detected by the application of gelatin enzyme spectrum and Western Blot technique in3days and1week in both the treatment group and the control group after corneal alkali burns.Results The high-level expression of matrix metalloproteinase-9was detected by the application of gelatinases spectrum in3days after corneal alkali burns, but it significantly decreased in1week and become almost indetectable in1month. By contrast, matrix metalloproteinases-2was low-leveled expressed in the3days after corneal alkali burns, but significantly increased in1week and was medium-leveled expressed in1month. The same results were proved by the application of Western Blot technique and immunohistochemistry technique that matrix metalloproteinases-9was high-leveled expressed in3days after corneal alkali burns and matrix metalloproteinases-2was high-leveled expressed in1week after corneal alkali burns. It was also observed that matrix metalloproteinase-1was persistently low-leveled expressed in3days,1week and1month after corneal alkali burns. On the other hand, it was observed that the high-leveled expression of matrix metalloproteinase-9was significantly inhibited in3days after corneal alkali burns by the intervention of Zn2+ ions solution by means of gelatinases spectrum and Western Blot technique. It was also observed that the expression of matrix metalloproteinase-2and matrix metalloproteinase-1were significantly inhibited in1week by the same means. The inhibition of the expression of matrix metalloproteinase-1,2and9by the intervention of Zn2+ions solution was proved to be all dose-related.Conclusions In the pathological damage process of corneal tissue, matrix metalloproteinases-9degradated the corneal epithelial basement membrane barriers to bring more infiltration of inflammatory substances in the corneal stroma after alkali burn.Howerver, matrix metalloproteinase-2played the more important role of corneal tissue damage.The activated Zn2+ions can effectively inhibit the expression of different kinds of matrix metalloproteinases which were observed with the ability to damage corneal tissue in different specific phases after corneal alkali burns. Therefore, the activated Zn2+ions can protect corneal tissue from the damage of alkali burn.